Set non-buffered mode for recipes.py and catch Ctrl-C.
Set non-buffered mode for recipes.py and catch Ctrl-C.

This should improve the local development experience when running
recipes.py. Bundled recipes already bypass this wrapper script, so this
shouldn't affect production.

R=a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org

Bug: 910369
Change-Id: I98e1ce0de86950653c1d0b8de89925847cc8ee47
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/recipes-py/+/1617302
Commit-Queue: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>
Auto-Submit: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>

luci/recipes-py,luci/recipes-py